1. Field of the Invention
The present invention relates to a method for manufacturing a retardation film, a polarizing plate, and a liquid crystal display, and particularly to a method for manufacturing a retardation film which does not easily cause stretching unevenness and has quality suitable for a liquid crystal display, a retardation film and a polarizing plate, and a liquid crystal display.
2. Description of the Related Art
The manufacture of a thermoplastic resin film is largely divided into a solution film-forming method and a melt film-forming method. The solution film-forming method is a method in which a dope in which a thermoplastic resin is dissolved in a solvent is cast from a die onto a support, for example, a cooling drum, to be in the shape of a film. On the other hand, the melt film-forming method is a method in which a thermoplastic resin is melted in an extruder and then extruded from a die onto a support, for example, a cooling drum, to be in the shape of a film. By performing uniaxial stretching in the machine (longitudinal) direction, or uniaxial stretching in the transverse direction (width direction), or biaxial stretching in the machine and transverse directions for a thermoplastic resin film formed by these methods, in-plane retardation (Re) and thickness direction retardation (Rth) are exhibited. The thermoplastic resin film exhibiting retardation Re and retardation Rth is used as the retardation film of a liquid crystal display element for intending to increase the viewing angle (see, for example, Japanese National Publication of International Patent Application No. 6-501040 and Japanese Patent Application Laid-Open No. 2001-42130).